Rotatable warning sign for vehicles



FIG. 1 is a perspective view of a rotatable warning sign for vehicles showing my new design, with the broken line showing for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a rotatable warning sign for vehicles, as shown and described. 